Infrared light (IR light), in particular near infrared (NIR), which is in a wavelength range of 0.78 μm to 3 μm, is used for therapeutic treatment in dermatology. The region of skin to be treated is usually irradiated areally. A local delimitation can be realized only in a complex fashion using conventional methods.
The use of OLEDs (OLED—organic light emitting diode) with IR emitters with individually adapted “perforated masks” in front of the OLED is expedient only to a limited extent in the case of IR emission, since most of the materials used for such a mask heat up and the local delimitation thus becomes indistinct. Moreover, the efficiency of OLED emitters generally decreases with increasing wavelength, that is to say that efficient IR OLEDs are difficult to produce. IR OLEDs exhibit higher self-heating than OLEDs which emit in the visible range of the electromagnetic spectrum (VIS), which is particularly disadvantageous for application in dermatology.
In medical technology, use is made of other IR sources, for example inorganic LEDs or IR lasers. The irradiation is locally delimited by in some instances complex optical systems. Hitherto, OLEDs have been adhesively bonded with conversion areas in a planar fashion, or a conversion layer has been applied directly to the substrate of the OLED, through which substrate the light is coupled out. In the case of contact methods, in medicine the high hygiene standards have to be taken into account. Materials are disposed of after contact with the patient.